A PTO assembly, such as a front PTO assembly, which has been typically used on an agricultural tractor, normally includes a constantly rotating input shaft which is driven by the tractor engine. The input or top shaft is connected by a transmission and a clutch to an output shaft. The input shaft drives a pump which supplies lubricant to the rotating components of the PTO assembly. The input shaft may be disconnected from the rest of the gear train, allowing the rest of the gear train to be static so the gears will not consume or waste any power. It would be desirable to have a PTO system wherein lubricating oil is directed to the input shaft when the input shaft is disconnected from the rest of the gear train.
The second task being performed is the shifting of the shuttle valve by the disconnect shaft to a position that reroutes the oil to the top shaft generating 4 bar pressure instead 18 bar for the system pressure.